‘Fossil’ groundwater is not immune to modern-day pollution

Deep well study finds contamination in at least 12,000-year-old water

DEEP WATER Deep groundwater wells, such as this hand-pumped well in Uganda being operated by water resources scientist Scott Jasechko, can contain mixes of old and young water and traces of pollution.

Merhawi GebreEgziabher

Groundwater that has lingered in Earth’s depths for more than 12,000 years is surprisingly vulnerable to modern pollution from human activities. Once in place, that pollution could stick around for thousands of years, researchers report online April 25 in Nature Geoscience. Scientists previously assumed such deep waters were largely immune to contamination from the surface.

“We can’t just drill deep and expect to run away from contaminants on the land surface,” says Scott Jasechko, a study coauthor and water resources scientist at the University of Calgary in Canada.

Groundwater quenches the thirst of billions of people worldwide and accounts for roughly 40 percent of the water used in agriculture. Water percolating from the surface into underground aquifers can carry pollutants such as pesticides and salt along for the ride.

Jasechko and colleagues weren’t looking

This article is only available to Science News subscribers. Already a subscriber? Log in now. Or subscribe today for full access.